.\" SCCSID: @(#)imp.4p	8.1	9/11/90.TH imp 4p VAX "" Unsupported.SH Nameimp \- IMP raw socket interface.SH Syntax.B #include <sys/socket.h>.br.B #include <netinet/in.h>.br.B #include <netimp/if_imp.h>.PP.B s = socket(AF_IMPLINK, SOCK_RAW, IMPLINK_IP);.SH DescriptionThe raw .PN imp socket provides direct access to the.MS imp 4network interface.  Users send packets throughthe interface using the .MS send 2calls, and receive packets with the.MS recv 2 ,calls.  All outgoing packets must have space for an 1822 96-bitleader on the front.  Likewise, packets receivedby the user will have this leader on the front.  The1822 leader and the legal values for the various fieldsare defined in the include file.RI < netimp/if_imp.h >..PPThe raw imp interface automatically installs the lengthand destination address in the 1822 leader of alloutgoing packets; these need not be filled in by the user..SH DiagnosticsAn operation on a socket may fail with one of the followingerrors:.TP 15[EISCONN]when trying to establish a connection on a socket whichalready has one, or when trying to send a datagram with the destinationaddress specified and the socket is already connected..TP 15[ENOTCONN]when trying to send a datagram, butno destination address is specified, and the socket hasn't beenconnected..TP 15[ENOBUFS]when the system runs out of memory foran internal data structure..TP 15[EADDRNOTAVAIL]when an attempt is made to create a socket with a network address for which no network interfaceexists..SH See Alsointro(4n), inet(4f), imp(4)